UPS Maintenance
To switch the UPS to maintenance bypass from Normal mode
1.Press the red button beside the Maintenance Bypass switch.
2.Turn the switch handle through the LINE position to the SERVICE position.
The battery circuit breaker trips, and the UPS is now bypassed, with the load powered by utility power.
3.The UPS automatically shuts down.
To return to Normal mode from maintenance bypass
1.If an optional isolation transformer is installed, switch the input circuit breaker to the ON position.
2.Turn the Maintenance Bypass switch to the LINE position.
The UPS starts up in Bypass mode, with the load still powered by utility power.
3.Switch the UPS battery circuit breaker to the ON position.
NOTE Wait until the 
indicator illuminates before proceeding to
Step 4; otherwise, power to the load may be lost.
4.Turn the Maintenance Bypass switch to the UPS position to return to Normal mode. The UPS is now powering the load.
84 | Powerware® 9155 UPS |